/*******************************************************************************
 * Copyright (c) 2000, 2013 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Marc R. Hoffmann <hoffmann@mountainminds.com> - Bug 284265 [JFace]
 *                  DialogSettings.save() silently ignores IOException
 *     Ruediger Herrmann <ruediger.herrmann@gmx.de> - bug 92518
 *******************************************************************************/
package org.eclipse.jface.dialogs;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Reader;
import java.io.Writer;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

/**
 * Concrete implementation of a dialog settings (<code>IDialogSettings</code>)
 * using a hash table and XML. The dialog store can be read
 * from and saved to a stream. All keys and values must be strings or array of
 * strings. Primitive types are converted to strings.
 * <p>
 * This class was not designed to be subclassed.
 *
 * Here is an example of using a DialogSettings:
 * </p>
 * <pre>
 * <code>
 * DialogSettings settings = new DialogSettings("root");
 * settings.put("Boolean1",true);
 * settings.put("Long1",100);
 * settings.put("Array1",new String[]{"aaaa1","bbbb1","cccc1"});
 * DialogSettings section = new DialogSettings("sectionName");
 * settings.addSection(section);
 * section.put("Int2",200);
 * section.put("Float2",1.1);
 * section.put("Array2",new String[]{"aaaa2","bbbb2","cccc2"});
 * settings.save("c:\\temp\\test\\dialog.xml");
 * </code>
 * </pre>
 * @noextend This class is not intended to be subclassed by clients.
 */

public class DialogSettings implements IDialogSettings {
    // The name of the DialogSettings.
    private String name;

    /* A Map of DialogSettings representing each sections in a DialogSettings.
     It maps the DialogSettings' name to the DialogSettings */
    private Map<String, IDialogSettings> sections;

    /* A Map with all the keys and values of this sections.
     Either the keys an values are restricted to strings. */
    private Map<String, String> items;

    // A Map with all the keys mapped to array of strings.
    private Map<String, String[]> arrayItems;

    private static final String TAG_SECTION = "section";//$NON-NLS-1$

    private static final String TAG_NAME = "name";//$NON-NLS-1$

    private static final String TAG_KEY = "key";//$NON-NLS-1$

    private static final String TAG_VALUE = "value";//$NON-NLS-1$

    private static final String TAG_LIST = "list";//$NON-NLS-1$

    private static final String TAG_ITEM = "item";//$NON-NLS-1$

    /**
     * Create an empty dialog settings which loads and saves its
     * content to a file.
     * Use the methods <code>load(String)</code> and <code>store(String)</code>
     * to load and store this dialog settings.
     *
     * @param sectionName the name of the section in the settings.
     */
    public DialogSettings(String sectionName) {
        name = sectionName;
        items = new HashMap<String, String>();
        arrayItems = new HashMap<String, String[]>();
        sections = new HashMap<String, IDialogSettings>();
    }

    /* (non-Javadoc)
     * Method declared on IDialogSettings.
     */
    @Override
    public IDialogSettings addNewSection(String sectionName) {
        DialogSettings section = new DialogSettings(sectionName);
        addSection(section);
        return section;
    }

    /* (non-Javadoc)
     * Method declared on IDialogSettings.
     */
    @Override
    public void addSection(IDialogSettings section) {
        sections.put(section.getName(), section);
    }

    /**
     * Remove a section in the receiver. If the given section does not exist,
     * nothing is done.
     *
     * @param section
     *            the section to be removed. Must not be <code>null</code>.
     * @since 3.9
     */
    public void removeSection(IDialogSettings section) {
        if (sections.get(section.getName()) == section) {
            sections.remove(section.getName());
        }
    }

    /**
     * Remove a section by name in the receiver. If the given section does not
     * exist, nothing is done.
     *
     * @param sectionName
     *            the name of the section to be removed.  Must not be <code>null</code>.
     * @return The dialog section removed, or <code>null</code> if it wasn't there.
     * @since 3.9
     */
    public IDialogSettings removeSection(String sectionName) {
        return sections.remove(sectionName);
    }

    /* (non-Javadoc)
     * Method declared on IDialogSettings.
     */
    @Override
    public String get(String key) {
        return items.get(key);
    }

    /* (non-Javadoc)
     * Method declared on IDialogSettings.
     */
    @Override
    public String[] getArray(String key) {
        return arrayItems.get(key);
    }

    /* (non-Javadoc)
     * Method declared on IDialogSettings.
     */
    @Override
    public boolean getBoolean(String key) {
        return Boolean.valueOf(items.get(key)).booleanValue();
    }

    /* (non-Javadoc)
     * Method declared on IDialogSettings.
     */
    @Override
    public double getDouble(String key) throws NumberFormatException {
        String setting = items.get(key);
        if (setting == null) {
            throw new NumberFormatException(
                    "There is no setting associated with the key \"" + key + "\"");//$NON-NLS-1$ //$NON-NLS-2$
        }

        return new Double(setting).doubleValue();
    }

    /* (non-Javadoc)
     * Method declared on IDialogSettings.
     */
    @Override
    public float getFloat(String key) throws NumberFormatException {
        String setting = items.get(key);
        if (setting == null) {
            throw new NumberFormatException(
                    "There is no setting associated with the key \"" + key + "\"");//$NON-NLS-1$ //$NON-NLS-2$
        }

        return new Float(setting).floatValue();
    }

    /* (non-Javadoc)
     * Method declared on IDialogSettings.
     */
    @Override
    public int getInt(String key) throws NumberFormatException {
        String setting = items.get(key);
        if (setting == null) {
            //new Integer(null) will throw a NumberFormatException and meet our spec, but this message
            //is clearer.
            throw new NumberFormatException(
                    "There is no setting associated with the key \"" + key + "\"");//$NON-NLS-1$ //$NON-NLS-2$
        }

        return new Integer(setting).intValue();
    }

    /* (non-Javadoc)
     * Method declared on IDialogSettings.
     */
    @Override
    public long getLong(String key) throws NumberFormatException {
        String setting = items.get(key);
        if (setting == null) {
            //new Long(null) will throw a NumberFormatException and meet our spec, but this message
            //is clearer.
            throw new NumberFormatException(
                    "There is no setting associated with the key \"" + key + "\"");//$NON-NLS-1$ //$NON-NLS-2$
        }

        return new Long(setting).longValue();
    }

    /* (non-Javadoc)
     * Method declared on IDialogSettings.
     */
    @Override
    public String getName() {
        return name;
    }

    /**
     * Returns a section with the given name in the given dialog settings. If
     * the section doesn't exist yet, then it is first created.
     *
     * @param settings
     *            the parent settings
     * @param sectionName
     *            the name of the section
     * @return the section
     *
     * @since 3.7
     */
    public static IDialogSettings getOrCreateSection(IDialogSettings settings,
                                                     String sectionName) {
        IDialogSettings section = settings.getSection(sectionName);
        if (section == null) {
            section = settings.addNewSection(sectionName);
        }
        return section;
    }

    /* (non-Javadoc)
     * Method declared on IDialogSettings.
     */
    @Override
    public IDialogSettings getSection(String sectionName) {
        return sections.get(sectionName);
    }

    /* (non-Javadoc)
     * Method declared on IDialogSettings.
     */
    @Override
    public IDialogSettings[] getSections() {
        Collection<IDialogSettings> values = sections.values();
        DialogSettings[] result = new DialogSettings[values.size()];
        values.toArray(result);
        return result;
    }

    /* (non-Javadoc)
     * Method declared on IDialogSettings.
     */
    @Override
    public void load(Reader r) {
        Document document = null;
        try {
            DocumentBuilder parser = DocumentBuilderFactory.newInstance()
                                                           .newDocumentBuilder();
            //		parser.setProcessNamespace(true);
            document = parser.parse(new InputSource(r));

            //Strip out any comments first
            Node root = document.getFirstChild();
            while (root.getNodeType() == Node.COMMENT_NODE) {
                document.removeChild(root);
                root = document.getFirstChild();
            }
            load(document, (Element)root);
        } catch (ParserConfigurationException e) {
            // ignore
        } catch (IOException e) {
            // ignore
        } catch (SAXException e) {
            // ignore
        }
    }

    /* (non-Javadoc)
     * Method declared on IDialogSettings.
     */
    @Override
    public void load(String fileName) throws IOException {
        FileInputStream stream = new FileInputStream(fileName);
        BufferedReader reader = new BufferedReader(new InputStreamReader(
                stream, "utf-8"));//$NON-NLS-1$
        load(reader);
        reader.close();
    }

    /* (non-Javadoc)
     * Load the setting from the <code>document</code>
     */
    private void load(Document document, Element root) {
        name = root.getAttribute(TAG_NAME);
        NodeList l = root.getElementsByTagName(TAG_ITEM);
        for (int i = 0; i < l.getLength(); i++) {
            Node n = l.item(i);
            if (root == n.getParentNode()) {
                String key = ((Element)l.item(i)).getAttribute(TAG_KEY);
                String value = ((Element)l.item(i)).getAttribute(TAG_VALUE);
                items.put(key, value);
            }
        }
        l = root.getElementsByTagName(TAG_LIST);
        for (int i = 0; i < l.getLength(); i++) {
            Node n = l.item(i);
            if (root == n.getParentNode()) {
                Element child = (Element)l.item(i);
                String key = child.getAttribute(TAG_KEY);
                NodeList list = child.getElementsByTagName(TAG_ITEM);
                List<String> valueList = new ArrayList<String>();
                for (int j = 0; j < list.getLength(); j++) {
                    Element node = (Element)list.item(j);
                    if (child == node.getParentNode()) {
                        valueList.add(node.getAttribute(TAG_VALUE));
                    }
                }
                String[] value = new String[valueList.size()];
                valueList.toArray(value);
                arrayItems.put(key, value);
            }
        }
        l = root.getElementsByTagName(TAG_SECTION);
        for (int i = 0; i < l.getLength(); i++) {
            Node n = l.item(i);
            if (root == n.getParentNode()) {
                DialogSettings s = new DialogSettings("NoName");//$NON-NLS-1$
                s.load(document, (Element)n);
                addSection(s);
            }
        }
    }

    /* (non-Javadoc)
     * Method declared on IDialogSettings.
     */
    @Override
    public void put(String key, String[] value) {
        arrayItems.put(key, value);
    }

    /* (non-Javadoc)
     * Method declared on IDialogSettings.
     */
    @Override
    public void put(String key, double value) {
        put(key, String.valueOf(value));
    }

    /* (non-Javadoc)
     * Method declared on IDialogSettings.
     */
    @Override
    public void put(String key, float value) {
        put(key, String.valueOf(value));
    }

    /* (non-Javadoc)
     * Method declared on IDialogSettings.
     */
    @Override
    public void put(String key, int value) {
        put(key, String.valueOf(value));
    }

    /* (non-Javadoc)
     * Method declared on IDialogSettings.
     */
    @Override
    public void put(String key, long value) {
        put(key, String.valueOf(value));
    }

    /* (non-Javadoc)
     * Method declared on IDialogSettings.
     */
    @Override
    public void put(String key, String value) {
        items.put(key, value);
    }

    /* (non-Javadoc)
     * Method declared on IDialogSettings.
     */
    @Override
    public void put(String key, boolean value) {
        put(key, String.valueOf(value));
    }

    /* (non-Javadoc)
     * Method declared on IDialogSettings.
     */
    @Override
    public void save(Writer writer) throws IOException {
        final XMLWriter xmlWriter = new XMLWriter(writer);
        save(xmlWriter);
        xmlWriter.flush();
    }

    /* (non-Javadoc)
     * Method declared on IDialogSettings.
     */
    @Override
    public void save(String fileName) throws IOException {
        FileOutputStream stream = new FileOutputStream(fileName);
        XMLWriter writer = new XMLWriter(stream);
        save(writer);
        writer.close();
    }

    /* (non-Javadoc)
     * Save the settings in the <code>document</code>.
     */
    private void save(XMLWriter out) throws IOException {
        HashMap<String, String> attributes = new HashMap<String, String>(2);
        attributes.put(TAG_NAME, name == null ? "" : name); //$NON-NLS-1$
        out.startTag(TAG_SECTION, attributes);
        attributes.clear();

        for (Iterator<String> i = items.keySet().iterator(); i.hasNext(); ) {
            String key = i.next();
            attributes.put(TAG_KEY, key == null ? "" : key); //$NON-NLS-1$
            String string = items.get(key);
            attributes.put(TAG_VALUE, string == null ? "" : string); //$NON-NLS-1$
            out.printTag(TAG_ITEM, attributes, true);
        }

        attributes.clear();
        for (Iterator<String> i = arrayItems.keySet().iterator(); i.hasNext(); ) {
            String key = i.next();
            attributes.put(TAG_KEY, key == null ? "" : key); //$NON-NLS-1$
            out.startTag(TAG_LIST, attributes);
            String[] value = arrayItems.get(key);
            attributes.clear();
            if (value != null) {
                for (int index = 0; index < value.length; index++) {
                    String string = value[index];
                    attributes.put(TAG_VALUE, string == null ? "" : string); //$NON-NLS-1$
                    out.printTag(TAG_ITEM, attributes, true);
                }
            }
            out.endTag(TAG_LIST);
            attributes.clear();
        }
        for (Iterator<IDialogSettings> i = sections.values().iterator(); i.hasNext(); ) {
            ((DialogSettings)i.next()).save(out);
        }
        out.endTag(TAG_SECTION);
    }

    /**
     * A simple XML writer.  Using this instead of the javax.xml.transform classes allows
     * compilation against JCL Foundation (bug 80059).
     */
    private static class XMLWriter extends BufferedWriter {

        /** current number of tabs to use for indent */
        protected int tab;

        /** the xml header */
        protected static final String XML_VERSION = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>"; //$NON-NLS-1$

        /**
         * Create a new XMLWriter
         * @param output the stream to write the output to
         * @throws IOException
         */
        public XMLWriter(OutputStream output) throws IOException {
            this(new OutputStreamWriter(output, "UTF8")); //$NON-NLS-1$
        }

        /**
         * Create a new XMLWriter
         * @param output the write to used when writing to
         * @throws IOException
         */
        public XMLWriter(Writer output) throws IOException {
            super(output);
            tab = 0;
            writeln(XML_VERSION);
        }

        private void writeln(String text) throws IOException {
            write(text);
            newLine();
        }

        /**
         * write the intended end tag
         * @param name the name of the tag to end
         * @throws IOException
         */
        public void endTag(String name) throws IOException {
            tab--;
            printTag("/" + name, null, false); //$NON-NLS-1$
        }

        private void printTabulation() throws IOException {
            for (int i = 0; i < tab; i++) {
                super.write('\t');
            }
        }

        /**
         * write the tag to the stream and format it by itending it and add new line after the tag
         * @param name the name of the tag
         * @param parameters map of parameters
         * @param close should the tag be ended automatically (=> empty tag)
         * @throws IOException
         */
        public void printTag(String name, HashMap<String, String> parameters, boolean close) throws IOException {
            printTag(name, parameters, true, true, close);
        }

        private void printTag(String name, HashMap<String, String> parameters, boolean shouldTab, boolean newLine, boolean close)
                throws IOException {
            StringBuffer sb = new StringBuffer();
            sb.append('<');
            sb.append(name);
            if (parameters != null) {
                for (Enumeration<String> e = Collections.enumeration(parameters.keySet()); e.hasMoreElements(); ) {
                    sb.append(" "); //$NON-NLS-1$
                    String key = e.nextElement();
                    sb.append(key);
                    sb.append("=\""); //$NON-NLS-1$
                    sb.append(getEscaped(String.valueOf(parameters.get(key))));
                    sb.append("\""); //$NON-NLS-1$
                }
            }
            if (close) {
                sb.append('/');
            }
            sb.append('>');
            if (shouldTab) {
                printTabulation();
            }
            if (newLine) {
                writeln(sb.toString());
            } else {
                write(sb.toString());
            }
        }

        /**
         * start the tag
         * @param name the name of the tag
         * @param parameters map of parameters
         * @throws IOException
         */
        public void startTag(String name, HashMap<String, String> parameters) throws IOException {
            startTag(name, parameters, true);
            tab++;
        }

        private void startTag(String name, HashMap<String, String> parameters, boolean newLine) throws IOException {
            printTag(name, parameters, true, newLine, false);
        }

        private static void appendEscapedChar(StringBuffer buffer, char c) {
            String replacement = getReplacement(c);
            if (replacement != null) {
                buffer.append('&');
                buffer.append(replacement);
                buffer.append(';');
            } else {
                buffer.append(c);
            }
        }

        private static String getEscaped(String s) {
            StringBuffer result = new StringBuffer(s.length() + 10);
            for (int i = 0; i < s.length(); ++i) {
                appendEscapedChar(result, s.charAt(i));
            }
            return result.toString();
        }

        private static String getReplacement(char c) {
            // Encode special XML characters into the equivalent character references.
            // The first five are defined by default for all XML documents.
            // The next three (#xD, #xA, #x9) are encoded to avoid them
            // being converted to spaces on deserialization
            switch (c) {
                case '<':
                    return "lt"; //$NON-NLS-1$
                case '>':
                    return "gt"; //$NON-NLS-1$
                case '"':
                    return "quot"; //$NON-NLS-1$
                case '\'':
                    return "apos"; //$NON-NLS-1$
                case '&':
                    return "amp"; //$NON-NLS-1$
                case '\r':
                    return "#x0D"; //$NON-NLS-1$
                case '\n':
                    return "#x0A"; //$NON-NLS-1$
                case '\u0009':
                    return "#x09"; //$NON-NLS-1$
            }
            return null;
        }
    }

}
